Safety cover for containers



July 7, 1942.

H. o. PARSONS 2,288,919

SAFETY COVER FOR CONTAINERS Filed Oct 14, 1-939 2 Sheets-Sheet 1 r W 0.INVENTOR.

y jA TTORNEY. I

July 7, 1942.

SAFETY COVER FOR CONTAINERS Filed bet. 14. 1959 2 Sheets-Sheet 2 F/ (2pmVINVENTOR.

H. o. PARSONS 2,288,919

Patented July 7, 1942 UNITED STATES PATENT OFFICE 2,288,919 SAFETY oovsnFOR CONTAINERS Harrison 0. Parsons, Houston, Tex.

Application October 14, 1939, Serial No. 299,462

3 Claims. (01. 220-55) The present invention relates to a safety coverfor containers. More particularly, the invention is directed to a coverto be used on tank car domes or to cover the upper end of gauges, suchas I have shown in my U. S. Patents 2,215,594, issued September 24,1940, and 2,228,481, issued January 14, 1941, and co-pending applicationSerial No. 299,461.

The shipping of volatile liquids in closed containers, such, forexample, as casinghead gasoline in tank cars, presents a considerablehazard. These containers are equipped with covers which must be removedfrom the container occasionally. If the workman is careless and removesa cover from a loaded container before first venting the contents of thecontainer to the atmosphere, the contents are likely to boil over. Thisnot only constitutes a hazard to the workers engaged in unloading thecar, but may also cause a substantial monetary loss.

It is therefore an object of the present invention to produce a coverfor containers which requires the contents of the container to be ventedto the atmosphere before the cover can be completely removed.

It is a further object of the present invention to produce a cover fortank car gauges, such as are disclosed in my copending applicationsmentioned above which will prevent the escape of volatile materials tothe atmosphere while the container is in transit, should the gauge leak,and which will prevent injury to the workmen in removing the cover incase such leakage allows a high pressure to build up under the cover.

Other objects and advantages will be seen from the description of theinvention taken in conjunction with the drawings in which Fig. 1 is atop view of a circular cover embodying the present invention;

Fig. 2 is a bottom view of the cover shown in Fig. 1;

Fig. 3 shows the rim of the manhole on which the cover shown in thepreceding figures may be placed;

Fig. 4 is a cross sectional view of the cover as shown by Fig. 1 takenalong line IV-IV and mounted on the manhole shown in Fig. 3;

Fig. 5 is a cross sectional view of the device shown in Fig. 3 takenalong the line VV;

Fig. 6 is another modification of the present invention showing anoblong manhole cover fitted with safety devices; and

Fig. 7 is a cross sectional view taken along th line VII-VII of Fig. 6.

Referring specifically to Fig. 1, the periphery of manner.

the cover is provided with spaced openings I, one part of which consistsof a circular opening 2 and another portion of which consists of slot 3.Ccuntersunk around slot 3 is a segment of circle 4. The manhole cover isalso provided with handles 5 and clevis 6.

As shown by Figs. 2 to 5, the bottom of the cover is equipped withspaced lugs I and reinforcing ribs 8. The center of the cover is alsoprovided with circular opening 9 through which a sampling device orsuitable pressure releasing device may be attached.

The manway ring or rim shown by the drawings is equipped with spacedholes H! which correspond in spacing to the holes I of the cover and aretapped so that they may be provided with studs H. The ring is alsoprovided with cavities l2 which correspond to lugs l of the cover. Oneend of the bottom of each of cavities I2 is arranged so that it slopesas shown by Fig. 5. Studs ll are provided with nuts l3 and pins I4extending through an opening near their upper portion to keep the nuts13 from being entirely removed from the studs. Made integral with nutsl3 are flanges l5 which are made of such a size that they fit snuglyinto the countersunk opening 4 with which the opening I is provided.

The manhole cover is attached to and removed from the manhole ring orrim in the following Assuming that the cover is screwed tightly inplace, the nuts l3 are loosened until their further movement isprevented, by pin 14. The cover is then rotated in a clockwisedirection. As the cover rotates, lugs 1 cooperating with sloping portionof groove 12 cause the cover to be raised from the manhole ring. Thisallows any vapor which may be in the tank to be exhausted from the tankthrough the space between the cover and ring before the cover iscompletely removed. After the cover is rotated so that washers l5coincide with circular opening 2 of the cover, the manhole cover may belifted directly from the ring.

Two safety measures are provided by the construction of the abovedescribed cover. In the first place the interior of the container mustbe vented to the atmosphere before the cover is completely removed. Thisis caused by the lugs cooperating with the slanting portion of slots 12and forcing the cover away from the manway. Another safety featureresides in the countersunk slots 4 surrounding the opening I. If afterall the bolts have been loosened from the cover there is such a pressureon the cover that it is blown directly upwardly, the flanges 15 of thenuts fit into the countersunk slots 4 and hold the cover so that itcannot be rotated. The cover thus remains under the control of theoperator and he is able to tighten it down and prevent the contents ofthe tank from boiling out.

In the modification of the device shown by Figs. 6 and '7 the rim of themanhole cover is provided with a slot [6 and the manway is provided withpin H. The length of the pin I1 is such that when the manhole cover israised so that it will slide over the top of this pin the top of thecover is immediately below the flanges l when nuts l5 are up against pinM. In this modification of the invention the operator in removing thecover from the manway must first loosen the nuts I3 to their fullestextent. The manhole cover must then be raised partially so as to allowthe cover to be ventedto the atmosphere before it may be rotated. If thecover has been stuck to the manway with pressure underneath, so thatwhen it is loosened it is blown directly upwardly, it cannot be rotatedbecause the countersunk slots 4 flt snugly around flange I5 of the nut.In this way the cover remains under the control of the operator duringthis critical period. If there is no excess pressure, the cover may berotated in the same manner as the previously described modificationafter being lifted, so that it clears pin IT and yet is not high enoughthat countersunk slots i fit around flanges [5. As the cover is rotated,flange I5 coincides with circular opening 2 at which point it may beremoved from the manway. In placing the cover on the manway the reversedprocedure is used.

In the modification shown by Fig. 6 the cover is made in an oblongshape. The openings l in the cover are placed around the periphery ofthe cover so that, when the cover is rotated, the

flanges I5 will be directly above the circular I openings I and willpass directly through them, when the cover is raised vertically. Theaxes of the openings l are placed on circles having the same center asthe cover, openings A being placed on one circle, openings B beingplaced on another circle having a greater radius, and openings C beingon a third circle of still greater radius. Other methods of positioningthese openings are also available, for example, by se lecting a flangeof suitable width, openings B and C may be placed on the same circle.

It is obvious that changes in size and arrangement of parts may be madein the above described invention. It is also evident that the safetydevice of the present invention is useful for other purposes than thoseabove referred to. For example, such a cover may be used for covering agauge used in gauging liquid containers or for other suitable purposeswhere a cover for an opening in high pressure vessels is required. Suchvariations are within the purview of the skill of the worker in art andare intended to be embraced by the appended claims in which it isintended to claim the invention as broadly as the prior art permit-S.

I claim:

1. A closure for pressure vessels comprising, in combination, a manwayrim formed integral with the pressure vessel, and a mating cover, saidcover being provided with openings spaced at regular intervals aroundits periphery, each of said openings being in the shape of a slotattached to a circle of greater diameter than the width of the slot andbeing pointed in the same direction as adjacent openings, said openingsbeing located at equal distances from the adjacent edge of the cover andsaid manway ring being provided with studs located at intervalscorresponding with the spacing of the openings of said cover, said studsbeing provided with nuts having flanges, the studs having a diameterless than the width of the slot portions of the openings and the flangeshaving a diameter less than the diameter of the circular portions, butgreater than the width of the slot portions of said openings, theoutside of the cover containing countersunk portions around the slot endof each opening of such size and shape as to receive said flanges, andthe insideof the cover provided with lugs, having their axis parallelwith the adjacent edge of the cover, the manway ring having cavities toreceive said lugs, a corresponding end of each of the cavities slantingup to the face of the ring so that the lugs force the face of the coveraway from the face of the ring as the cover is given an angular motion.

2. A device as in claim 1 in which the cover and ring are circular inform.

3. A device as in claim 1 in which the cover and ring are oval in form.

HARRISON O. PARSONS.

